1. Field of the Invention
This invention relates to a grinding and polishing machine and, more particularly, to a machine for grinding and polishing fiber optic termini.
2. Description of Related Art
A fiber optic terminus typically includes a housing and an optical fiber extending through the housing. It is important that the distal end of the fiber be flush with an end face of the housing and that the plane of the distal end be perpendicular to the longitudinal axis of the fiber. Accuracy is very important, and tolerances may be, for example, plus or minus 0.0002 inch.
At one stage in the manufacture of a fiber optic terminus, the optical fiber extends through the housing, and a projecting segment of the optical fiber extends beyond the end face of the housing and terminates in a distal end. For example, the projecting segment may have a length of approximately 0.030 inch. It is necessary to very accurately grind off the projecting segment so that the distal end of the optical fiber is flat, flush with the end face and perpendicular to the longitudinal axis of the fiber. The end face of the housing should also be perpendicular to the axis of the fiber, and the distal end of the fiber should have an optical finish.
It is known to position a group of fiber optic termini in a fixture and to accomplish the grinding and polishing by manually holding the fixture and the fibers against grinding and polishing wheels. This requires a skilled operator and is fatiguing to the operator. Automated equipment is also available for holding a fixture with one or more fiber optic termini against grinding and/or polishing wheels.
A primary problem with all of these prior art techniques is that, at some point during the grinding operation, the fixture which holds the fiber optic termini is brought into contact with the abrasive used for the grinding operation. The abrasive contact between the abrasive and the fixture causes the fixture to wear relatively rapidly. To reduce wear on the fixture, it is known to use hard diamond pads on the fixture and a softer abrasive, such as aluminum oxide. However, this relatively softer abrasive is not the most effective abrasive for the grinding operation, and the time required for the grinding operation is increased.
A problem associated with automating of the grinding and polishing operations is in the construction of a grinding and polishing apparatus with sufficient accuracy to yield the precision results required. More specifically, the problem is in obtaining the very accurate parallel and perpendicular relationships required for precision grinding and polishing of fiber optic termini. For example, in a precision grinding apparatus, the rotational axes of the grinding and polishing abrasives should be parallel, and the abrasives must be perpendicular to the axes about which the abrasives rotate.